Broadband Sound Absorption in a Composite of Localized Aluminum Foam and Microperforated Plates

A composite structure (L-LDMPP) consisting of localized aluminum foam, a localized microperforated plate (MPP), and a double-layer MPP is proposed to enhance sound absorption. A simulation model using COMSOL is developed to predict the sound absorption coefficient and investigate the acoustic benefits of localized aluminum foam and localized MPP. A comparative analysis is performed to evaluate the sound absorption performance of four configurations: L-SMPP (localized aluminum foam with a single-layer MPP), L-DMPP (localized aluminum foam with a double-layer MPP), L-LSMPP (localized aluminum foam with a localized MPP and a single-layer MPP), and L-LDMPP (localized aluminum foam with a localized MPP and a double-layer MPP). The model's accuracy is validated against experimental data. Results show that localized aluminum foam, localized MPP, and double-layer MPP optimize acoustic impedance matching. The sound absorption characteristics of L-LDMPP are divided into two domains: the resonance acoustic domain, influenced by the double-layer MPP structure behind the localized aluminum foam, and the coupled acoustic domain, influenced by both the localized aluminum foam and localized MPP.